West Pacific/2015/09W/Archive/12
Public advisory TYPHOON CHAN-HOM PUBLIC ADVISORY NUMBER 12 WIKI-HURRICANES FORECASTING CENTER 6:00 AM JST FRI JUL 03 2015 ...CHAN-HOM TO POSE A SIGNIFICANT THREAT TO THE MARIANA ISLANDS... SUMMARY OF 6:00 AM JST...21:00 UTC...INFORMATION ------------------------------------------------------------------- LOCATION...10.1N, 148.2E CENTER POSITION CONFIDENCE: LOW ABOUT 325 MI...520KM SE OF HAGATNA, GUAM MAXIMUM SUSTAINED WINDS...65 KT...75 MPH...120 KM/H MINIMUM BAROMETRIC PRESSURE...985 MB...29.09 INCHES PRESENT MOVEMENT...E AT 2 KT...3 MPH...6 KM/H DISCUSSION AND 48-HOUR OUTLOOK --------------------------------------------- At 6:00 am JST, the center of Typhoon Chan-Hom was situated near 10.1N, 148.2E, or about 325 miles (520 kilometers) southeast of Hagatna, Guam. Maximum sustained winds were 65 knots (75 mph, 120 km/h), with higher gusts. The minimum barometric pressure was 985 millibars (hPa; 29.09 inHg), and the cyclone was tracking east at 2 knots (3 mph, 6 km/h). Chan-hom is expected to continue strengthening steadily as it approaches the Mariana Islands over the next two days. Chan-hom is a significant threat to life and property across the Mariana Islands. Take the necessary precautions now! NEXT ADVISORY ------------------- Next complete advisory at 12:00 pm JST. $$ Forecaster YE Discussion TYPHOON CHAN-HOM DISCUSSION NUMBER 12 WIKI-HURRICANES FORECASTING CENTER 6:00 AM JST FRI JUL 03 2015 The rapid deepening observed overnight has slowed this morning. Instead, Chan-Hom is slowly deepening. The deep convection has become more concentrated and more organized, and the rainbands have increased. Multiple microwave passes have suggested that there is probably at least some sort of mid-level eye feature. Intensity estimate remained unchanged from the previous package, with the exception of the JTWC increasing their estimate to T4.0. Therefore, Chan-Hom remains a 65 knot typhoon. Chan-hom is now moving east, if not northeast. What was once Invest 94W — the low-pressure area southwest of Chan-hom that could have complicated the forecast track — has now been absorbed by Chan-hom. Thus, the current steering for Chan-hom will largely be driven by the subtropical ridge to its north in the short-term, before a trough is expected to provide a weakness in the ridge, causing Chan-hom to sharply curve northwestward and into the Mariana Islands. The new forecast track is a little south in the short-term, but more north in the long-run, where it places more weight to the European model (ECMWF) than the American one (GFS) at longer-intervals. It is unlikely that Chan-Hom, while building an inner core as we speak, will finish one off over the next 6-12 hours, due to a combination of dry air, and wind shear. As such, only slow intensification is shown in the term. Conditions are set to improve for Chan-hom over the coming days as it enters into an area with less shear. The typhoon is still located in moderate to strong shear. In fact, wind shear for now appears to be increasing, and it would not shock me if Chan-Ham briefly weakened to a tropical storm by noon, but once Chan-Hom moved into areas just to the north and west, shear drops down to values lower than 10 knots, and in addition to favorable sea surface temperatures and oceanic heat content, anticyclonic flow and as a result favorable outflow channels will begin developing later on. Furthermore, the storm is expect to finish off it's inner core by the next day or so. Rapid intensification could begin thereafter, but this is not shown due to the possibility of land interaction. Assuming it's inner core is not disrupted, and I don't expect it to since none of the models that forecast the entire freaking global expect it to and is thus not reflected below, rapid intensification will likely begin by then, compared to slow and steady intensification. The intensities on day 4 and day 5 are uncertain, because in this basin, eyewall replacement cyclones are common, and one can not predict these long-range. As such, an unrealistically slow intensification phase is shown above. Interests in the the Mariana Islands should continue to monitor this system. These areas should expect to see life-threatening typhoon conditions and take any necessary precautionary measures immediately. INIT 02/2100Z 10.1N 148.2E 65 KT 75 MPH 12H 03/0600Z 10.1N 147.E 65 KT 75 MPH 24H 03/1800Z 10.9N 147.0E 70 KT 80 MPH 36H 04/0600Z 12.6N 146.7E 75 KT 85 MPH 48H 04/1800Z 14.3N 146.1E 85 KT 100 MPH ... NEAR MARIANA ISLANDS 72H 05/1800Z 17.7N 142.8E 120 KT 140 MPH 96H 06/1800Z 21.2N 140.0E 130 KT 150 MPH 120H 07/1800Z 21.0N 136.0E 140 KT 160 MPH $$ Forecaster YE